PCOS is a risk for serious disorders
Women with PCOS are at increased risk of Type 2 diabetes, pregnancy diabetes, pre-eclampsia, fatty liver, the metabolic syndrome, coronary artery disease, strokes, autoimmune thyroid disease (resulting in underactive or overactive thyroid), Alzheimer's disease and endometrial cancer in the long term if left untreated.
Risks of PCOS
- Miscarriage
- Type 2 Diabetes
- Gestational (Pregnancy) Diabetes
- Pre-eclampsia
- Fatty Liver
- The Metabolic Syndrome
- Cardiovascular Disease
- Autoimmune Thyroid Disease (resulting in underactive or overactive thyroid)
- Strokes
- Alzheimer's Disease
- Endometrial Cancer
Some of these medical conditions e.g. Alzheimer's disease and endometrial cancer are worst case scenarios and would only be seen in neglected and untreated women with PCOS.
Miscarriage
While miscarriage seems an unfortunate chance event for most couples, it is clear that women with PCOS may be at increased risk of early pregnancy loss (EPL), that is, within the first 12 weeks of pregnancy. PCOS is associated with a 30 to 40% rate of EPL. The hormonal environment in PCOS may interfere with egg development within the follicle and/or disrupt embryo implantation within the uterus. The lining of the uterus (endometrium) in PCOS fails to secrete glycodelin that prevents the "rejection" of the early embryo by the endometrial immune response. The embryo, being 50% foreign to the mother, has to be tolerated by her womb as a transplant.
In most cases no apparent cause can be found for the pregnancy loss although defects in the early developing embryo have been identified in up to 60% of cases. High blood insulin, typical of women with PCOS is an independent risk factor for early pregnancy loss. Women with PCOS are also more likely to have autoimmune thyroid disease, another risk factor for EPL.
Gestational diabetes
Almost 50% of women with PCOS develop gestational diabetes. It is therefore advisable that they be screened at 12 weeks of pregnancy for diabetes and thyroid disease (see below). Moreover, all women with PCOS should be given a glucose tolerance test between 24-28 weeks of pregnancy. More than half the women with gestational diabetes turn out to have PCOS when tested after they had delivered.
Pre-eclampsia
Pre-eclampsia is a serious complication of late pregnancy characterised by a sudden increase in blood pressure, excessive weight gain, swelling and protein in the urine. It requires immediate medical attention. Insulin resistance is a known risk factor for pre-eclampsia. Women with PCOS are particularly at risk during their first pregnancy. Pre-eclampsia runs in families.
Cardiovascular disease
As an insulin resistant state, PCOS poses a significant risk for cardiovascular disease through central obesity, abnormal blood lipids, increased inflammatory markers, and an increase in the tendency of blood to coagulate and in the level of homocsyteine. All these factors, as well as high fasting insulin, are recognized risk factors for heart disease in the population at large.
The Metabolic Syndrome
Severe insulin resistance in PCOS will eventually have an impact on most body functions leading to the Metabolic Syndrome. The syndrome also goes under the sobriquet of “Syndrome X” or “Dysmetabolic" syndrome. Overweight women with PCOS not infrequently have at least 2-3 of the following characteristics:
- a large waist circumference (also known as central obesity)
- high blood glucose (in the fasting state before breakfast or after meals)
- high blood pressure high blood triglyceride ("trigs")
- high levels of small, dense cholesterol
- low levels of HDL (the good cholesterol)
- fatty liver (non-alcoholic steatohepatitis or NASH)
- increased blood homocysteine levels.
Autoimmune Thyroid Disease
Recent research found that women with PCOS are more likely to develop thyroid autoimmunity than women without the syndrome. Some of these women may go on to develop underactive or overactive thyroid. Even if they are only positive for thyroid antibodies and have normal thyroid function tests, they are at a greater risk of EPL and for post-partum thyroid disease. We recommend that women with PCOS should have their thyroid function including thyroid antibodies tested when they are planning pregnancy, but failing that then at the time of booking.
The requirements of thyroid hormone replacement increases during pregnancy in those known to be hypothyroid and taking thyroxin or in women with PCOS who are discovered to be hyperthyroid during screening.

Regulation of the thyroid by the pituitary gland. Adapted from 'The Thyroid Book' by Krames Health and Safety Education
Radioactive
scan of an overactive thyroid due to Graves’ disease Note that the thyroid
gland is diffusely enlarged and avidly takes up the radioactive iodide used
to scan the thyroid, giving the gland its dark appearance. Graves’ disease
is an autoimmune disease in which the immune system 'rebels' against the
thyroid and makes antibodies against the receptor for the Thyroid Stimulating
Hormone (see Figure above). By contrast to other antibodies that destroy
their targets, the antibodies in Graves’ disease stimulate the thyroid to
work overtime. Graves’ disease was first described by Robert Graves in 1825,
an Irish physician.
Radioactive
scan of a patient with hypothyroidism due to autoimmune thyroiditis. By
contrast to the scan in the figure above, the pattern of uptake is patchy
and less intense. The fact that there is an area of relatively greater concentration
of radioactive iodine over the right lobe was because this patient also had
a non-cancerous nodule in the right lobe. Scans are not good way of making
a diagnosis of underactive thyroid. Blood tests are far more sensitive to
establish thyroid function. 